Please note that if push notifications was rejected after a user had been using your app for some time Pushwoosh unregisters this device from pushes. In case a user rejects to receive pushes right upon installation, Pushwoosh will not know about it because device would not register for pushes. I think that the "getUnregisteredDevices" API method would be useful for your case. With this method you can retrieve a list of unsubscribed devices.